Posted on:7/12/2012

Supreme Court ruled in Massachusetts v. EPA that greenhouse gases are covered by the CAA's definition of air pollutant and that EPA must determine whether or not emissions of greenhouse gases from new motor vehicles cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare.

On June 6, the U.S. Court of Appeals-D.C. Circuit upheld EPA's Endangerment Finding and greenhouse gas regulations issued under the Clean Air Act (CAA) for passenger vehicles and CAA permitting for stationary sources.

Said EPA Administrator, Lisa P. Jackson: "Today's ruling is a strong validation of, in the Court's own words, the "unambiguously correct" approach we have taken in responding to the 2007 Supreme Court decision. I am pleased that the U.S. Court of Appeals for the D.C. Circuit found that EPA followed both the science and the law in taking common-sense, reasonable actions to address the very real threat of climate change by limiting greenhouse gas pollution from the largest sources."

In 2007 the Supreme Court ruled in Massachusetts v. EPA that greenhouse gases are covered by the CAA's definition of air pollutant and that EPA must determine whether or not emissions of greenhouse gases from new motor vehicles cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare.

EPA was challenged through a group of lawsuits over its actions resulting from the Supreme Court decision to address greenhouse gases, including:

The Light Duty Vehicle Rule, in which EPA coordinated with the National Highway Traffic Safety Administration to develop harmonized regulations to reduce greenhouse gas emissions and improve the fuel economy of light-duty vehicles.

The Tailoring Rule, in which EPA set greenhouse gas emission thresholds to define when permits under the New Source Review Prevention Significant Deterioration (PSD) and title V Operating Permit programs are required for new and existing industrial facilities.